#1141 Split TOTP permissions for add/remove, refactor TOTP services

- Split TotpService further into GenerateTotpService and TotpAuthenticator, which wraps the GoogleAuthenticator impl
- Add missing tests for the services
- Change GenerateTotpService's interface to behave like a collection for more intuitive method behavior

src/main/java/fr/xephi/authme/security/totp/GenerateTotpService.java

@@ -0,0 +1,69 @@
+package fr.xephi.authme.security.totp;
+
+import fr.xephi.authme.initialization.HasCleanup;
+import fr.xephi.authme.security.totp.TotpAuthenticator.TotpGenerationResult;
+import fr.xephi.authme.util.expiring.ExpiringMap;
+import org.bukkit.entity.Player;
+
+import javax.inject.Inject;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Handles the generation of new TOTP secrets for players.
+ */
+public class GenerateTotpService implements HasCleanup {
+
+    private static final int NEW_TOTP_KEY_EXPIRATION_MINUTES = 5;
+
+    private final ExpiringMap<String, TotpGenerationResult> totpKeys;
+
+    @Inject
+    private TotpAuthenticator totpAuthenticator;
+
+    GenerateTotpService() {
+        this.totpKeys = new ExpiringMap<>(NEW_TOTP_KEY_EXPIRATION_MINUTES, TimeUnit.MINUTES);
+    }
+
+    /**
+     * Generates a new TOTP key and returns the corresponding QR code.
+     *
+     * @param player the player to save the TOTP key for
+     * @return TOTP generation result
+     */
+    public TotpGenerationResult generateTotpKey(Player player) {
+        TotpGenerationResult credentials = totpAuthenticator.generateTotpKey(player);
+        totpKeys.put(player.getName().toLowerCase(), credentials);
+        return credentials;
+    }
+
+    /**
+     * Returns the generated TOTP secret of a player, if available and not yet expired.
+     *
+     * @param player the player to retrieve the TOTP key for
+     * @return TOTP generation result
+     */
+    public TotpGenerationResult getGeneratedTotpKey(Player player) {
+        return totpKeys.get(player.getName().toLowerCase());
+    }
+
+    public void removeGenerateTotpKey(Player player) {
+        totpKeys.remove(player.getName().toLowerCase());
+    }
+
+    /**
+     * Returns whether the given totp code is correct for the generated TOTP key of the player.
+     *
+     * @param player the player to verify the code for
+     * @param totpCode the totp code to verify with the generated secret
+     * @return true if the input code is correct, false if the code is invalid or no unexpired totp key is available
+     */
+    public boolean isTotpCodeCorrectForGeneratedTotpKey(Player player, String totpCode) {
+        TotpGenerationResult totpDetails = totpKeys.get(player.getName().toLowerCase());
+        return totpDetails != null && totpAuthenticator.checkCode(totpDetails.getTotpKey(), totpCode);
+    }
+
+    @Override
+    public void performCleanup() {
+        totpKeys.removeExpiredEntries();
+    }
+}

src/main/java/fr/xephi/authme/security/totp/TotpAuthenticator.java

@@ -0,0 +1,67 @@
+package fr.xephi.authme.security.totp;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.warrenstrange.googleauth.GoogleAuthenticator;
+import com.warrenstrange.googleauth.GoogleAuthenticatorKey;
+import com.warrenstrange.googleauth.GoogleAuthenticatorQRGenerator;
+import com.warrenstrange.googleauth.IGoogleAuthenticator;
+import fr.xephi.authme.service.BukkitService;
+import org.bukkit.entity.Player;
+
+import javax.inject.Inject;
+
+/**
+ * Provides rudimentary TOTP functions (wraps third-party TOTP implementation).
+ */
+public class TotpAuthenticator {
+
+    private final IGoogleAuthenticator authenticator;
+    private final BukkitService bukkitService;
+
+
+    @Inject
+    TotpAuthenticator(BukkitService bukkitService) {
+        this(new GoogleAuthenticator(), bukkitService);
+    }
+
+    @VisibleForTesting
+    TotpAuthenticator(IGoogleAuthenticator authenticator, BukkitService bukkitService) {
+        this.authenticator = authenticator;
+        this.bukkitService = bukkitService;
+    }
+
+    public boolean checkCode(String totpKey, String inputCode) {
+        try {
+            Integer totpCode = Integer.valueOf(inputCode);
+            return authenticator.authorize(totpKey, totpCode);
+        } catch (NumberFormatException e) {
+            // ignore
+        }
+        return false;
+    }
+
+    public TotpGenerationResult generateTotpKey(Player player) {
+        GoogleAuthenticatorKey credentials = authenticator.createCredentials();
+        String qrCodeUrl = GoogleAuthenticatorQRGenerator.getOtpAuthURL(
+            bukkitService.getIp(), player.getName(), credentials);
+        return new TotpGenerationResult(credentials.getKey(), qrCodeUrl);
+    }
+
+    public static final class TotpGenerationResult {
+        private final String totpKey;
+        private final String authenticatorQrCodeUrl;
+
+        TotpGenerationResult(String totpKey, String authenticatorQrCodeUrl) {
+            this.totpKey = totpKey;
+            this.authenticatorQrCodeUrl = authenticatorQrCodeUrl;
+        }
+
+        public String getTotpKey() {
+            return totpKey;
+        }
+
+        public String getAuthenticatorQrCodeUrl() {
+            return authenticatorQrCodeUrl;
+        }
+    }
+}

src/main/java/fr/xephi/authme/security/totp/TotpService.java

@@ -0,0 +1,18 @@
+package fr.xephi.authme.security.totp;
+
+import fr.xephi.authme.data.auth.PlayerAuth;
+
+import javax.inject.Inject;
+
+/**
+ * Service for TOTP actions.
+ */
+public class TotpService {
+
+    @Inject
+    private TotpAuthenticator totpAuthenticator;
+
+    public boolean verifyCode(PlayerAuth auth, String totpCode) {
+        return totpAuthenticator.checkCode(auth.getTotpKey(), totpCode);
+    }
+}